SciPost Submission Page
Magnetic properties of a multicomponent intermetallic compound Tb0.25Dy0.25Ho0.25Er0.25Al2
by P. K. Jesla, J. Arout Chelvane and R. Nirmala
This is not the latest submitted version.
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Jesla P K |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202207_00022v1 (pdf) |
| Date submitted: | 2022-07-15 13:00 |
| Submitted by: | P K, Jesla |
| Submitted to: | SciPost Physics Proceedings |
| Proceedings issue: | International Conference on Strongly Correlated Electron Systems (SCES2022) |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
|
| Approach: | Experimental |
Abstract
Polycrystalline multicomponent Laves phase rare earth intermetallic compound Tb0.25Dy0.25Ho0.25Er0.25Al2 has been synthesized by arc-melting and characterized by powder X-ray diffraction, magnetization and heat capacity measurements. The sample has MgCu2-type cubic structure (space group Fd-3m) at 300 K. The compound Tb0.25Dy0.25Ho0.25Er0.25Al2 orders ferromagnetically at 50 K (TC). This is value is almost equal to the average of the ferromagnetic ordering temperatures of the individual RAl2 (R = Tb, Dy, Ho and Er) compounds. Field dependence of magnetization below TC indicates soft-ferromagnetic nature. From the magnetization vs field data obtained near TC and the temperature dependence of heat capacity, low field magnetocaloric effect has been estimated
Current status:
Reports on this Submission
Strengths
1: Complete analysis of multi-component rare-earth inter metallic with an eye towards magneto-caloric effect.
Weaknesses
Presents data but does not go much beyond the basics.
Report
This paper meets the criteria for the SCES conference proceedings.
Requested changes
This is an overall well written and complete study of a multi component inter-metallic. I have a few small comments that will improve reading for non-experts.
1: Section 2: The acronym EDAX is introduced. I don’t see where the A is coming from. I believe it is generally abbreviated to EDX.
2: Is there a reference for the relaxation technique used to measure the specific heat.
3: On page 2 it is written that the saturation magnetization is 9.5 Bohr magnetron. Looking at Fig. 2b, it seems to be 7.5 mu_B/f.u. Please explain.
4: Similarly, it is stated that this is less than expected for collinear alignment. Please add the expected value.
5: The MCE of this compound is called ‘normal’, ‘substantial’ and ‘moderate’. These are rather qualitative and seem to be inconsistent with each other. It would help the reader to know what defines this and how it compares to other materials.
6: On page 4, just above Eq. 2 it is written ’…and shifts to the right as evidenced in ferromagnetic.’ Please change to ‘…shifts to higher temperature…’
7: A reference or explanation of Eq. 3 would be appreciated.
8: It would be useful to have comparison values of the adiabatic temperature changes for RAl2 compounds. Either a reference or maybe add them to table 1?
9: The sentence ‘Thus, substitution of multi-component…’ is unclear. What is the de Gennes factor and how does it connect to having multiple principal elements?
Author: Jesla P K on 2023-01-25 [id 3271]
(in reply to Report 1 on 2023-01-07)Answers for the reviewer’s questions:
1. Section 2: The acronym EDAX is introduced. I don’t see where the A is coming from. I believe it is generally abbreviated to EDX.
Energy dispersive analysis of X-rays is abbreviated either as EDX or EDAX in literature. We now use EDX in the manuscript.
2. Is there a reference for the relaxation technique used to measure the specific heat?
Yes, we have now added the following reference. J.C. Lashley, M.F. Hundley, A. Migliori, J.L. Sarrao, P.G. Pagliuso, T.W. Darling, M. Jaime, J.C. Cooley, W.L. Hults, L. Morales, D.J. Thoma, J.L. Smith, J. Boerio-Goates, B.F. Woodfield, G.R. Stewart, R.A. Fisher, N.E. Phillips, Critical examination of heat capacity measurements made on a Quantum Design physical property measurement system, Cryogenics 43(6), 369(2003) doi:10.1016/S0011-2275(03)00092-4.
3. On page 2 it is written that the saturation magnetization is 9.5 Bohr magnetron. Looking at Fig. 2b, it seems to be 7.5 mu_B/f.u. Please explain.
Saturation magnetization is calculated from M vs H data by extending magnetization to infinite magnetic field. It is the value of M when 1/H tends to zero. The value obtained is 9 Bohr magneton. This is now correctly mentioned in the manuscript.
4. Similarly, it is stated that this is less than expected for collinear alignment. Please add the expected value.
The value expected for collinear alignment is 9.5 Bohr magneton.
5. The MCE of this compound is called ‘normal’, ‘substantial’ and ‘moderate’. These are rather qualitative and seem to be inconsistent with each other. It would help the reader to know what defines this and how it compares to other materials.
Magnetocaloric effect is called ‘normal’ if -ΔSM is positive (as observed in ferromagnets) and it is called ‘inverse magnetocaloric effect’ if -ΔSM is negative (as observed in antiferromagnets). The -ΔSM value for 15 kOe field change is comparable with that of the individual RAl2 (R = Tb, Dy, Ho and Er) and these are moderate when compared to that of giant magnetocaloric materials.
6. On page 4, just above Eq. 2 it is written ’…and shifts to the right as evidenced in ferromagnetic.’ Please change to ‘…shifts to higher temperature…’
Yes, this change has been done.
7. A reference or explanation of Eq. 3 would be appreciated.
A reference [M. Foldeaki, et al., J. Appl. Phys. 82 (1) (1997) 309] is now added.
8. It would be useful to have comparison values of the adiabatic temperature changes for RAl2 compounds. Either a reference or maybe add them to table 1?
Yes this is added to table 1 in the revised manuscript.
Compound a
(Å) TC (K) ΔSmax
(Jkg-1K-1) ΔTad (K) ΔH (kOe) Reference
TbAl2 7.867 105 5.5 2.2 20 [8], [12]
DyAl2 7.8370 65 9.7 3.6 20 [8], [12]
HoAl2 7.8182 29 12.8 4.6 20 [8], [12]
ErAl2 7.7957 13 22.6 20 [8], [12]
Tb0.25Dy0.25Ho0.25Er0.25Al2 7.8394 50 5.5 2.4 15 This work
9. The sentence ‘Thus, substitution of multi-component…’ is unclear. What is the de Gennes factor and how does it connect to having multiple principal elements?
Transition temperature of isostructural RAl2 compounds scales with de Gennes factor
G= (g-1)2 J(J+1) where g is the gyromagnetic ratio. The multi-component system also follows the de Gennes rule. We have now added this reference in the revised manuscript. R. M. Bozorth, Magnetic Properties of Compounds and Solid Solutions of Rare‐Earth Metals, Journal of Applied Physics 38, 1366 (1967); https://doi.org/10.1063/1.1709625.
Attachment:
Answers_for_the_questions_22Jan2023_1.pdf